System for operation of a gearbox for a motor vehicle

Abstract

Described herein is a system for operating a gearbox that includes: a first shaft having a first longitudinal axis; a first actuator assembly operatively connected to the first shaft; a second shaft having a second longitudinal axis; a second actuator assembly operatively connected to the second shaft; and a plurality of engagement elements connected in rotation to the second shaft. The first shaft is hollow, is fitted on the second shaft, and is axially movable relative to the second shaft. The plurality of engagement elements are moreover connected in translation to the first shaft and are axially movable therewith along the first longitudinal axis and relative to the second shaft. The first and second shafts can be operated independently of one another for execution of the movements of selection and engagement of the gears of the gearbox.

The invention claimed is: 
     
       1. A system for operating a gearbox, comprising:
 a first shaft having a first longitudinal axis; 
 a first actuator assembly operatively connected to the first shaft; 
 a second shaft having a second longitudinal axis; 
 a second actuator assembly operatively connected to the second shaft; and 
 a plurality of engagement elements connected in rotation to said second shaft; 
 wherein: 
 the first shaft is hollow, is fitted on said second shaft, and is axially movable relative to the second shaft; 
 said plurality of engagement elements are connected in translation to said first shaft and are axially movable therewith along said first longitudinal axis and relative to the second shaft; 
 the first actuator assembly is configured for imparting on said first shaft a movement of translation along the first longitudinal axis, said movement of translation being transferred to the plurality of engagement elements connected in translation to the first shaft; and 
 the second actuator assembly is configured for imparting on said second shaft a movement of rotation about the second longitudinal axis, said movement of rotation being transferred to said plurality of engagement elements, which are connected in rotation to the second shaft. 
 
     
     
       2. The operating system according to  claim 1 , wherein said second shaft is axially fixed. 
     
     
       3. The operating system according to  claim 1 , wherein each engagement element of the plurality of engagement elements is connected in rotation to said second shaft by means of a shape coupling of an axially sliding type. 
     
     
       4. The operating system according to  claim 1 , wherein said first actuator assembly comprises a first rotary actuator, a pinion connected in rotation to an output shaft of said first rotary actuator, and a rack with which said pinion meshes, said rack being coupled in translation to said first shaft. 
     
     
       5. The operating system according to  claim 4 , wherein said first shaft is freely rotatable with respect to said rack. 
     
     
       6. The operating system according to  claim 4 , wherein said second actuator assembly comprises a second rotary actuator, a transmission having an input element coupled to an output shaft of said second rotary actuator, and an output element connected in rotation to said second shaft, the transmission being configured for transmitting motion from said input element to said output element. 
     
     
       7. The operating system according to  claim 6 , wherein said second actuator assembly comprises a mounting flange, said mounting flange comprising a seat for housing said second rotary actuator, and a rotation support for the pinion of said first rotary actuator. 
     
     
       8. The operating system according to  claim 6 , wherein the input element of said transmission is a another pinion connected to the output shaft of said second rotary actuator, said another pinion meshing with a first toothing of an idle gear wheel having a first diameter, said idle gear wheel having a second toothing with a second diameter, smaller than the first diameter, said second toothing meshing with a toothed sector connected in rotation to said second shaft and defining said output element of the transmission. 
     
     
       9. The operating system according to  claim 4 , wherein each rotary actuator is an electric motor. 
     
     
       10. The operating system according to  claim 1 , wherein said first shaft comprises a plurality of segments coupled together via the plurality of engagement elements and connected in rotation thereto. 
     
     
       11. A gearbox comprising:
 an operating system according to  claim 1 ; 
 a primary shaft rotatable about a respective axis and comprising a first plurality of gear wheels connected in rotation thereto; 
 a first secondary shaft and a second secondary shaft rotatable about respective axes parallel to one another and to the respective axis of the primary shaft, the first and second secondary shafts comprising a second plurality and a third plurality of gear wheels, respectively, each of said second and third plurality of gear wheels meshing with a corresponding gear wheel of said first plurality of gear wheels of said primary shaft to define a plurality of forward gears of said gearbox and a reverse gear; and 
 the gear wheels of the second plurality and of the third plurality of gear wheels being mounted idle on the respective secondary shaft and being selectively coupleable in rotation to the respective secondary shaft by means of corresponding engagement devices, each of the engagement devices being controlled by means of a corresponding fork engagement device having a control seat configured for being selectively engaged by an engagement element of the plurality of engagement elements of said operating system; 
 wherein the first shaft and the second shaft of said operating system are arranged with an orientation transverse with respect to said primary shaft, said first secondary shaft, and said second secondary shaft. 
 
     
     
       12. The gearbox according to  claim 11 , further comprising a parking device comprising a pawl, which rocks about an axis parallel to the axis of the second secondary shaft and is countered elastically in rotation,
 said pawl being configured for engagement with a sprocket, which is connected in rotation to the second secondary shaft, and being engageable in said sprocket via sliding of a slider, said slider being axially movable by being engaged by an engagement element of said plurality of engagement elements and being driven in rotation via said second shaft and a second motor-reducer assembly.